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Hazawa M, Amemori S, Nishiyama Y, Iga Y, Iwashima Y, Kobayashi A, Nagatani H, Mizuno M, Takahashi K, Wong RW. A light-switching pyrene probe to detect phase-separated biomolecules. iScience 2021; 24:102865. [PMID: 34386728 PMCID: PMC8346672 DOI: 10.1016/j.isci.2021.102865] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 06/04/2021] [Accepted: 07/12/2021] [Indexed: 11/16/2022] Open
Abstract
Biomolecules may undergo liquid-liquid phase separation (LLPS) to spatiotemporally compartmentalize and regulate diverse biological processes. Because the number of tools to directly probe LLPS is limited (ie. FRAP, FRET, fluorescence microscopy, fluorescence anisotropy, circular dichroism, etc.), the physicochemical traits of phase-separated condensates remain largely elusive. Here, we introduce a light-switching dipyrene probe (Pyr-A) that forms monomers in either hydrophobic or viscous environments, and intramolecular excimers in aqueous solutions. By exploiting their distinct fluorescence emission spectra, we used fluorescent microscopic imaging to study phase-separated condensates formed by in vitro protein droplets and membraneless intracellular organelles (centrosomes). Ratiometric measurement of excimer and monomer fluorescence intensities showed that protein droplets became hydrophobic and viscous as their size increased. Moreover, centrosomes became hydrophobic and viscous during maturation. Our results show that Pyr-A is a valuable tool to characterize LLPS and enhance our understanding of phase separation underlying biological functions.
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Affiliation(s)
- Masaharu Hazawa
- Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa, Japan
- Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, Japan
- WPI Nano Life Science Institute, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Shogo Amemori
- Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa, Japan
- Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, Japan
- NanoMaterials Research Institute, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Yoshio Nishiyama
- Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Yoshihiro Iga
- Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Yuki Iwashima
- Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Akiko Kobayashi
- Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Hirohisa Nagatani
- Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Motohiro Mizuno
- Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa, Japan
- Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, Japan
- NanoMaterials Research Institute, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Kenji Takahashi
- Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Richard W. Wong
- Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa, Japan
- Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, Japan
- WPI Nano Life Science Institute, Kanazawa University, Kanazawa, Ishikawa, Japan
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Nishizawa I, Ajito H, Gonmori Y, Katoh R, Ichikawa T, Nemoto N. Synthesis and characterization of poly(tetramethylsilarylenesiloxane) derivatives with oligothiophene based moiety. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.01.069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Maeda H, Suzuki T, Segi M. Effects of substituents in silyl groups on the absorption, fluorescence and structural properties of 1,3,6,8-tetrasilylpyrenes. Photochem Photobiol Sci 2018; 17:781-792. [PMID: 29741552 DOI: 10.1039/c8pp00135a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
1,3,6,8-Tetrasilylpyrenes and related germyl and stannyl derivatives were synthesized, and their absorption and fluorescence spectroscopic and structural properties were elucidated. The results show that the UV-vis absorption maxima of these substances in CH2Cl2 solutions shift to longer wavelengths as the size of the alkyl groups and numbers of phenyl groups on silicon increase. Fluorescence quantum yields of tetrasilylpyrenes in cyclohexane are larger than that of pyrene, and a pentamethyldisilyl derivative has an emission efficiency of 0.79. Except in the case of the SiMe2H derivative, excimer emission was not observed in concentrated solutions of these substances. The SiMe2H and SiMe3 derivatives were shown to form CT complexes with tetracyanoethylene in CH2Cl2 solutions. The calculated energy barriers for rotation of the silyl groups about the Si-C bond increase as the steric bulk of the silyl group increases. 29Si NMR chemical shifts were found to depend on the sizes of the alkyl groups and numbers of phenyl groups. Data arising from theoretical calculations suggest that the silyl groups act as electron-donating groups, and the donating ability of the groups decreases in the order SiR3 > GeR3 > SnR3.
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Affiliation(s)
- Hajime Maeda
- Division of Material Chemistry, Graduate School of Natural Science and Technology Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan.
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Niko Y, Kawauchi S, Otsu S, Tokumaru K, Konishi GI. Fluorescence enhancement of pyrene chromophores induced by alkyl groups through σ-π conjugation: systematic synthesis of primary, secondary, and tertiary alkylated pyrenes at the 1, 3, 6, and 8 positions and their photophysical properties. J Org Chem 2013; 78:3196-207. [PMID: 23425392 DOI: 10.1021/jo400128c] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We have systematically synthesized 1-, 3-, 6-, and 8-alkyl-substituted pyrene derivatives using the latest synthesis methods and investigated the effects of alkyl substitution on the photophysical properties of the pyrene chromophore. Like the trimethylsilyl group, which is known to enhance the fluorescence properties of some chromophores through σ*-π* conjugation, alkyl groups (primary, secondary, and tertiary) enhanced the fluorescence quantum yield of the pyrene chromophore through σ-π conjugation in most cases. While these enhancements in the fluorescence quantum yield were beyond expectations, the results were supported by absolute measurements. These results also indicate that ubiquitous alkyl groups can be used to tune the photophysical properties of the pyrene chromophore, as well as to improve the solubility or prevent aggregation. In other words, they can be used to develop new photofunctional materials.
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Affiliation(s)
- Yosuke Niko
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, O-okayama, Tokyo 152-8552, Japan
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